When e107plugin::install() is called, it does not rescan the e107_plugins folder for any plugins that may have been added since e107plugin was instantiated. New plugins would not be added into the database.

Since plugin addons are found from the database, any addons from the new plugin will be skipped during installation. ^{_{This may cause troubleshooting headaches like it did for me.}}

Plugins need to be registered in the database before installation.